# Temperature calibration for of the shelf sensor nodes

Terminology:

I have been experimenting with of the shelf temperature sensor nodes. The exact device in question is an Aeon Labs LLC, Aeontec Z-Wave MultiSensor 6.

I got the information that to reach the accuracy defined in the specs (+-1 Celsius) the sensor nodes have to be recalibrated after installation. The recalibration is done by using an offset value to even the sensor node temperature reading with a referent temperature reading.

I can reason the calibration of analog sensors where the voltage levels of the power can't be known at production time hence additional calibration is required once the power source is available.

This is an of the shelf sensor node intended to be used as a consumer electronic product. I haven't yet witnessed cheap dedicated thermometers ever needing calibration.

Questions:

• Under what circumstances does a temperature sensor need calibration? (given that there are so many sensor nodes that don't offer the calibration mechanism)
• Is the precision of +-1 Celsius a difficult requirement to achieve and can be severely reduced (3 Celsius difference between nodes placed next to each other) just by the fact that the sensor has been moved to a different environment (example. from loft to basement)?
• Part 2 of your questions is confusing. Calibration is location specific. – Sean Houlihane May 20 '16 at 9:41

• Many of these factors are not stable which makes the claimed accuracy rather unimportant. What do you mean by this? What would be the meaning of a temperature measurement without an accuracy? – TheMeaningfulEngineer May 20 '16 at 9:50